Method using monolayer etch masks in combination with printed masks

Abstract

A method to pattern films into dimensions smaller than the printed pixel mask size. A printed mask is deposited on a thin film on a substrate. The second mask layer is selectively deposited onto the film, but not to the printed mask. A third mask is then printed onto the substrate to pattern a portion of the second mask. Certain solvents are then used to remove the printed mask but not the mask layer on the thin film. The mask layer is then used to form a pattern on the thin film in combination with etching. The features formed in the thin film are smaller than the smallest dimension of the printed mask. The coated mask layer can be a self-assembled mono-layer or other material that selectively binds to the thin film.

1. A method of patterning a feature on a substrate, the method comprising:
 depositing a thin film layer on a substrate; 
 printing a first mask to form a fine feature wherein the first printed mask has a minimum dimension and the fine feature is a gap with a distance smaller than the minimum; dimension of the first printed mask: 
 depositing a second mask around the first mask and on top of the thin film layer; 
 printing a third mask registered to the first mask to define a region of the second mask that is smaller than the smallest region of the first printed mask; 
 removing the exposed portions of the second printed mask; 
 removing the first and third printed masks relative to the remaining portions of the second printed mask; and 
 removing areas of the thin film layer not protected by the remaining second printed mask. 
 
   
   
     2. The method defined in  claim 1  wherein the thin film layer comprises a metal or an alloy or a dielectric. 
   
   
     3. The method defined in  claim 1  wherein the first and third printed masks comprise a phase change material. 
   
   
     4. The method defined in  claim 1  wherein the second mask comprises a material that selectively attaches to the thin film layer. 
   
   
     5. The method defined in  claim 4  wherein the material comprises a monolayer. 
   
   
     6. A method of fabricating an electronic device with fine features, the method comprising:
 depositing a thin film layer on a substrate; 
 printing a first mask to form a fine feature wherein the first printed mask has a minimum dimension and the fine feature is a gap with a distance smaller then- 4 he than the minimum of the first printed mask; depositing a second mask around the first printed mask and on top of the thin film layer; 
 printing a third mask registered to the first printed mask to define a region of the second mask that is smaller than the smallest region of the first printed mask; 
 removing the exposed portions of the second printed mask; 
 removing the first and third printed masks relative to the remaining portions of the second printed mask; 
 removing portions of the thin film layer not protected by the second printed mask; 
 removing the remaining portions of the second printed mask; and 
 forming at least one electrical component of an electronic device. 
 
   
   
     7. The method defined in  claim 6  wherein the thin film layer comprises a metal or an alloy or a dielectric. 
   
   
     8. The method defined in  claim 6  wherein the first and third printed masks comprise a phase change material. 
   
   
     9. The method defined in  claim 6  wherein the second mask comprises a material that selectively attaches to the thin film layer. 
   
   
     10. The method defined in  claim 9  wherein the material comprises a monolayer. 
   
   
     11. The method of  claim 6  where the electronic device comprises an amorphous silicon thin film transistor or an organic thin film transistor. 
   
   
     12. A method of making a portion of a thin film transistor array, the method comprising:
 depositing a thin film layer on a substrate; 
 printing a first mask to form a fine feature wherein the first printed mask has a minimum dimension and the fine feature is a gap with a distance smaller than the minimum of the first printed mask; 
 depositing a second mask around the first printed mask and on top of the thin film layer; 
 printing a third mask registered to the first printed mask to define a region of the second printed mask that is smaller than the smallest region of the first printed mask; 
 removing the exposed portions of the second printed mask; 
 removing the first and third masks relative to the remaining portions of the second printed mask; 
 removing regions of the thin film layer not protected by the second printed mask; and 
 removing the remaining portions of the second printed mask. 
 
   
   
     13. The method defined in  claim 12  wherein the portion of the thin film transistor array comprises the gate electrode region for a thin film transistor and an address line that connects the gate electrode region to other gate electrode regions of the thin film transistor array. 
   
   
     14. The method defined in  claim 13  wherein the gate electrode and the address line are co-planar. 
   
   
     15. The method defined in  claim 12  wherein the portion of the thin film transistor array comprises the source and drain electrodes for a thin film transistor and an address line that connects one of the source or drain electrodes to the other of the electrodes on the thin film transistor array. 
   
   
     16. The method defined in  claim 12  wherein the thin film layer comprises a metal, an alloy, or a dielectric. 
   
   
     17. The method defined in  claim 12  wherein the first and third printed masks comprise a phase change material. 
   
   
     18. The method defined in  claim 12  wherein the second mask comprises a material that selectively attaches to the thin film layer. 
   
   
     19. The method defined in  claim 18  wherein the material comprises a monolayer.